Drift flux curves

When the data abruptly departs from the drift flux curve, a change in the flow regime is assumed to occur flooding, according to Wallis (3). It was visually observed that increased coalescence and slugging occurred when the experimental data diverged from the drift flux curve. 

Figure 3. Drift-flux curves for 9.5-cm diameter column ([ ) PE spargers, (O)...

The transition between the two mdoels is not yet clear, however it would seem departure from the drift-flux curve may indicate this transition. It remains to be determined the precise form... 

Once the slip velocity is known, the drift flux can be obtained by using Eq. (128), which is termed the hydrodynamic curve. On the other hand, for the given operating conditions with specified superficial velocities of particles and fluid, the drift flux can also be directly obtained through the operating line given by... 

Figure 16 Dimensionless drift flux for air-FCC particles normalized by terminal velocity of single particle (the dashed operating lines are marked with corresponding dimensionless superficial gas velocity and solids velocity the solid lines correspond to the hydrodynamic curve Ax/dp denotes the dimensionless grid size (A) with Wen and Yu drag (B) with EMMS drag under different grid sizes) (Ullah et al, 2013a).

Figures 3(a) and 3(b) show the computed fraction profiles of component A and B in the liquid film corresponding to, respectively, run 1 and run 6 from Table 1. Figure 3(a) shows that low fractions of A and B produce straight profiles, whereas high fractions of A and B result in curved profiles [see Fig. 3(b)]. The latter is due to the fact that the mass fluxes consist of a diffusive part as well as a convective (i.e. drift) part. This is also the reason why the fraction of B possesses a gradient, although the flux of component B equals zero.

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